Liquid cooling unit



May 16, 1950 F. G. PECK LIQUID COOLING UNIT Filed March 30, 1949 F l GFRED- s. PECK,

Patented May 16,, 1950 UN I N '1" OFF l-CE LIQUID ICOOISING UNIT "FretlGLPeck, Hag-'crstowmMii.

Application March 30, 1949 ,Serial No. 84,317

1 invention relates to improvements in cooling units, and moreparticularly to an improved immersion or drop-in cooling unit designedespecially Ltor can-type milk coolers,but

suitable of other uses requiring eflicient cooling of-aliquid ina tankor container.

,Drop-in cooling units are well known but, as previously constructed,have the disadvantage of excessive weight and insome designs unbalanceddistribution of weight. Such results not only in difficulties inpacking, shipping and removing the .unit from the cooler cabinet forservicing,

-etc.,-but has alsogiven rise to the practice of the unit'being-draggedacross 'theiifioor andbecoming contaminated and thereby contaminatingthe liquid in which the unit is immersed.

Stated broadly, the present invention contemplates and aims to providean improved selfcontained package type cooling unit which ischaracterized bylightness in weight as compared to prior units, sothatit may readily be handledin shipment and use, and which moreover maybe readily removed from the cooler cabinet and delivered to aservicecenter in a compact shipping container. 7

Another-object of the-invention is the provision of; a drop-in coolingunit-of improved design, according to which the unit comprises .avertical stack-up of component ,parts, with the weight of the heaviercomponents, i. e. sealed-compressor unit, agitator and .fan motor andcondenser, centered on the axis of the unit and in .a relatively smallspace which for a standard unit is approximately 1 3" ,x :14

Still another aimof the invention .is the provision of a drop-in coolingunit as aforesaid, which is characterized, as compared to prior unitsserving similarfunctiomby-a reduction in the numberof parts,'byalowerpower consumption, and by increased efiiciency.

Another object of theinveritionis the provision of a drop-in coolingunit employing a sleevetype evaporator of compact, economical con--struction giving a high heat transfer surface, and which is readilycleanable, the "latter being important in maintaining sanitationstandards. A still further object of the invention is the hprovision ofa drop-in cooling unit as last above characterized, wherein theevaporator is supported solely 'by tubular structural members which also"function as refrigerant passages, thereby introducing economies inconstruction, and moreover "allowing the maintenance "of anfe'fiic'ierit head of refrigerant 'in .the evaporator evaporator. Thisarrangement is also or "advantage 'in tha't the "tubular structuralmember providing the suction riser, by proper"selection "(Ifsi2e,'furnis'hesfa convenient separatlon'c'ha-mher for entrained liquidnot boiled mi in the evaporator, "allowing it to "fall "back into "the"'boiler, with the result thatthesuction riser acts as a surge chamber.The construction wherein tubular structural members providetherefrigerant passages for "theevaporator also as 'sists in maintainingsmooth, readily 'c'ieanable surfaces.

The above and other objects and advantages of the improved drop-incooling unit will be seen from the following description thereof,takenwiththe accompanying drawing, in which Fi g. 1 is a part-sectionalelevational view i1- "lustrating theimpr'oved drop-in 'cooling'unit of'theinvention; and

Fig.2 is a sectional view of a can-type cooler illustrating the'mannerof use of acooling unit as shown-in Fig. 1.

The illustrated drop-in cooler is intended for use .in coolingwatereontained in the tank of a can type milk "cooler, thus in turn tocool,milk in-cans whichare immersed in the cooled water. A typicalcooler ll! is illustrated liniFig. '2 and comprises an insulated cabinethousing a water tank Ill whichiaiin useAilled .tothedesiredilevl. ,Thecabinet .top may include .a i'fixed section 12 andahinged cover 13, thelfixed section supporting the cooling unit as shown, andiorthis purposebeing provided with ,alholecl'lilthrough which the evaporatormay'beflowerefd into the waterin the tank. The hinged cover section 13provides flrfor convenient access .to the interior of the cabinet asrequired inlowering the milk cansinto the cabinet and lifting themtherefrom.

As seen in Fig. ,1, the improved cooling tunit employs a horizontalsupporting plate or deck member F6 adapted 'to .be mouritedlon theflfixed section I 2 ,of 'the cabinet top. In a standard cooling unit-built in accordance with 'theprin- .ciples of the invention, "thesupporting deck is rectangular and its dimensions are 13" .x 1'14".Supported from and spaced above the 'deck by inverted LU-s'haped'bnadkets 11, 11a is ,a sealed motor-compressor unit "1113 which isvertically arranged. In the space between said unit and the deck memberis mounted a motor 119 also vertically arranged and with itsaxisinalignment with that (of the motor-compressor unit. The deckmeniber Italso supports a two-section .condenser, "th'esetions of which,,designate'd'fifl, 20a, are connected in circuitby asuitable connectionsleeve 21 along their longitudinal edges.

(not shown) and are disposed symmetrically to the sides of the axis ofthe motor I9. A single section condenser disposed to encircle the motorI9 may be substituted for the two-section condenser as described.

The head shaft of the motor [9 drives a fan 22 which, it will beobserved, operates in a plane somewhat above the upper line of thecondenser and below the motor compressor unit. The space between theU-shaped brackets [1, Ha is closed, front and rear, by bridging plates,of which the front plate 23 is shown. Accordingly, when the fan 22 isplaced in operation, it draws in air through the condenser sections,thereby cooling them, and also direct air upwardly against and about themotor-compressor unit, thereby cooling the latter also.

Supported from below the deck I6 is an evaporator generally designated25 adapted to be immersed in the liquid of the tank, thereby to cool thesame. As shown, the evaporator comprises interfitting inner and outersleeves 26, 27, the inner sleeve having a helical groove formed thereinas by rolling, which terminates near the ends of the sleeve. The outersleeve 21 is of plain, cylindrical form and when assembled with theinner sleeve forms therewith a helical refrigerant passage designated28. The inlet to said passage is provided by an opening 29 formed in theouter sleeve adjacent its lower edge, and the outlet from said passageis formed by an outer sleeve opening 39 provided adjacent its upper end.

The evaporator 25 is supported from the deck It by two verticallydisposed structural members 32, 33, and it is a feature of the inventionthat said structural supporting members are formed tubular so that, inaddition to their supporting function, they also provide refrigerantpassages for the evaporator.

The lower ends of the structural members 32, 33 extend the full axiallength of the evaporator and for said length are formed with half-roundsection, being welded to the evaporator outer By this arrangement, theevaporator is rigidly aifixed to the structural members and, by virtueof the fact that their half-round lower ends of the semicircular contourmerge nicely into the curvature of the outer sleeve 28, no crevices areformed in the joint between structural members and evaporator, with theresult that the joint may be readily cleaned.

In the construction illustrated, one tubular structural member 32connects to the low level inlet 29 to the helical refrigerant passage ofthe evaporator, and the other structural member 32 communicates with thehigh level or outlet opening 30 of the aforesaid passage. At its upperend, the structural supporting member 32 connects through a suitableunion with the low tem-- perature side of the expansion valve 35, andthe upper end of the other structural member 33 connects through asuitable union with a tube 36 connected to the suction side of thecompressor.

The expansion valve 35 is connected to the liquid discharge side of thecondenser section 20a through a receiver 3'! and liquid line 31a.Preferably, the tube 36 is disposed in heat-exchange relation withliquid line 31a but is not so shown. It will be understood that the highpressure or discharge side of the compressor is connected by tube 38with the condenser section 20.

- Conventional controls are provided, such as a standard start-and-stopswitch control 40 for the sealed motor-compressor unit, with a bulbtypeelement 4| carried within the evaporator to extend into the liquid ofthe tank and connected by a capillary 42 to the switch control, and athermostatic bulb 43 connected by a. capillary 44 to the thermostaticexpansion valve. The capillaries 42, 43 are preferably clipped to thetubular structural members 32, 33, as shown, and, being disposed on theinner peripheries thereof, are protected against damage.

To effect circulation of the liquid in the tank, an impeller 46 isprovided, being housed within the tubular or sleeve-form evaporator anddisposed near the lower end thereof. The impeller is driven by avertical shaft 41 journaled for rotation in a lower bearing 48 mountedin a, spider afiixed to the upper edge of the evaporator, and beingdrivingly connected with the tail shaft of motor H) by a suitablecoupling.

It will be observed that the evaporator 25 is disposed on the commonaxis of motor-compressor unit l8 and motor :9, and that the axis of theimpeller shaft all coincides with said common axis. Accordingly, theunit is characterized by a vertical stackup of component parts, withweight centered substantially in the small space represented by thedimensions of the deck memher [6. This arrangement has numerouspractical advantages in packaging and shipment Moreover, it permits theunit to be readily lifted from the cooler and delivered to a servicecenter in a compact shipping container. Due to its lightweightconstruction, taken with the feature of balanced distribution of weight,a cooling unit as aforesaid can be readily handled without the necessityof dragging it across a floor, for example.

As compared to prior cooling units employing a separate motor fordriving the agitator or impeller, the use of a single motor for drivingboth the cooling fan and impeller introduces economy in construction,reduced power consumption, overall increased efliciency, and increasedsimplicity in maintenance.

Due to the construction of the evaporator 25, additional reduction ininitial cost is obtained. Consequent to such construction, theevaporator will maintain a high external pressure, i. e. pressure withinthe helical refrigerant passage, without collapse or rupture. The use ofa helical refrigerant passage provided by a helical groove in the innersleeve making up the evaporator has the advantage of increased heattransfer area. Moreover, due to the high velocities of the liquid-vapormixture, oils present in the refrigerant circuit are constantly sweptalong this passage without undue concentration and returned to thecompressor crank case. This absence of a heavy oil film or oil pocket onthe heat transfer surfaces results in high heat transfer. The helicalconvolutions also furnish an irregular although smooth surface on thewater side which induces a high degree of scrubbing action, therebyeflectively increasing the film coefiicient of heat transfer, reducingthe film resistance on the water side. It will be noted that this highheat transfer on the water side does not present crevices which arelikely to be fouled up by foreign matter accumulating in the tankliquid. In case of a deposit on the heat transfer surface, such mayreadily be cleaned, so that adequate sanitation standards aremaintained.

The utilization of the tubular supporting members as refrigerantpassages as herein provided not only involves an economy but also allowsthe maintenance of an efficient head of refrigerant on the evaporatorproper, thus maintaining a fully flooded evaporator. By proper selectionof size of the tubular supporting member functioning as the suctionriser (member 33), the latter may form a convenient separation chamberfor entrained liquid not boiled off in the evaporator, allowing it tofall back into the boiler. In other words, the suction riser functionsas a "surge chamber. The construction wherein tubular structural membersare combined with refrigerant passages also assists in maintainingsmooth, readily cleanable surfaces.

As many changes could be made in carrying out the above constructionwithout departing from the scope of the invention, it is intended thatall matter contained in the above description or shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

I claim:

1. A cooling unit for a tank cooler comprisin in combination, asupporting plate adapted to be mounted on the top of the'cooler cabinet,a sealed motor-compressor unit and a motor mounted on said plate, bothsaid motor-compressor unit and said motor being vertically arranged anddisposed on a common axis, a condenser also mounted on said plate withits weight distributed to opposite sides of said axis, a fan driven bysaid motor for cooling the condenser and motor-compressor unit, anopen-ended evaporator depending from said plate to extend into theliquid contained in the tank, an impeller for agitating said liquid, anda shaft extending between motor and impeller for driving the latter fromthe motor, said evaporator, agitator and shaft being also disposed onsaid common axis.

2. A cooling unit as set forth in claim 1, wherein the sealedmotor-compressor unit is disposed above the fan and impeller motor, andthe fan is disposed intermediate said unit and said motor.

3. A cooling unit as set forth in claim 1, Wherein the condenser is madein two sections which are disposed symmetrically to the sides of the fanand impeller motor.

5. A cooling unit as set forth in claim 1, wherein the sealedmotor-compressor unit is disposed above the motor, the condenser is madein two sections which are disposed symmetrically to the sides of themotor, and the fan is disposed intermediate said unit and said motor,thereby to draw in air through the condenser sections and to directcooling air on to said unit.

6. A cooling unit for a tank cooler comprising, in combination, asupporting plate adapted to be mounted on the top of the cooler, arefrigeration system mounted from said plate including a sealedcompressor unit and a condenser disposed above the plate, a sleeve-typeevaporator disposed below the plate to extend into the liquid containedin the tank, said evaporator comprising interfitting inner and outersleeves, the inner sleeve having a helical groove terminating adjacentthe ends thereof and providing a helical refrigerant passage, the outersleeve having an opening adjacent its lower end providing an inlet tothe refrigerant passage and an opening adjacent its upper end providingan outlet from said passage, and tubular structural members supportingthe evaporator from the plate and. providing refrigerant passages, saidmembers extending substantially the full length of the evaporator andhaving half-round section for said length and being each connected alongboth longitudinal edges to the outer sleeve, one of said tubularstructural members communicating with the inlet to the helicalrefrigerant passage, and the other tubular structural membercommunicating with the outlet from said passage.

FRED G. PECK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 939,021 Hendrix Nov. 2, 19091,992,988 Blahnik Mar. 5, 1935 2,050,192 Melcher Aug. 4, 1936 2,188,839Markley Jan. 30, 1940 2,203,439 Oliver June 4, 1940 2,455,162 DonnellyNov. 30, 1948

